I am using Google cloud's GKE for my kubernetes operations.

I am trying to restrict access to the users that access the clusters using command line. I have applied IAM roles in Google cloud and given view role to the Service accounts and users. It all works fine if we use it through api or "--as " in kubectl commands but when someone tries to do a kubectl create an object without specifying "--as" object still gets created with "default" service account of that particular namespace.

To overcome this problem we gave restricted access to "default" service account but still we were able to create objects.

$ kubectl auth can-i create deploy --as default -n test-rbac
no

$ kubectl run nginx-test-24 -n test-rbac --image=nginx
deployment.apps "nginx-test-24" created

$ kubectl describe  rolebinding default-view -n test-rbac
Name:         default-view
Labels:       <none>
 Annotations:  <none>
Role:
  Kind:  ClusterRole
  Name:  view
Subjects:
  Kind            Name     Namespace
  ----            ----     ---------
  ServiceAccount  default  test-rbac

I expect users who are accessing cluster through CLI should not be able to create objects if they dont have permisssions, even if they dont use "--as" flag they should be restricted.